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Dietary protein intake does not modulate daily myofibrillar protein synthesis rates or loss of muscle mass and function during short-term immobilization in young men: a randomized controlled trial.
Kilroe, SP, Fulford, J, Jackman, S, Holwerda, A, Gijsen, A, van Loon, L, Wall, BT
The American journal of clinical nutrition. 2021;(3):548-561
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Abstract
BACKGROUND Short-term (<1 wk) muscle disuse lowers daily myofibrillar protein synthesis (MyoPS) rates resulting in muscle mass loss. The understanding of how daily dietary protein intake influences such muscle deconditioning requires further investigation. OBJECTIVES To assess the influence of graded dietary protein intakes on daily MyoPS rates and the loss of muscle mass during 3 d of disuse. METHODS Thirty-three healthy young men (aged 22 ± 1 y; BMI = 23 ± 1 kg/m2) initially consumed the same standardized diet for 5 d, providing 1.6 g protein/kg body mass/d. Thereafter, participants underwent a 3-d period of unilateral leg immobilization during which they were randomly assigned to 1 of 3 eucaloric diets containing relatively high, low, or no protein (HIGH: 1.6, LOW: 0.5, NO: 0.15 g protein/kg/d; n = 11 per group). One day prior to immobilization participants ingested 400 mL deuterated water (D2O) with 50-mL doses consumed daily thereafter. Prior to and immediately after immobilization upper leg bilateral MRI scans and vastus lateralis muscle biopsies were performed to measure quadriceps muscle volume and daily MyoPS rates, respectively. RESULTS Quadriceps muscle volume of the control legs remained unchanged throughout the experiment (P > 0.05). Immobilization led to 2.3 ± 0.4%, 2.7 ± 0.2%, and 2.0 ± 0.4% decreases in quadriceps muscle volume (P < 0.05) of the immobilized leg in the HIGH, LOW, and NO groups (P < 0.05), respectively, with no significant differences between groups (P > 0.05). D2O ingestion resulted in comparable plasma free [2H]-alanine enrichments during immobilization (∼2.5 mole percentage excess) across groups (P > 0.05). Daily MyoPS rates during immobilization were 30 ± 2% (HIGH), 26 ± 3% (LOW), and 27 ± 2% (NO) lower in the immobilized compared with the control leg, with no significant differences between groups (P > 0.05). CONCLUSIONS Three days of muscle disuse induces considerable declines in muscle mass and daily MyoPS rates. However, daily protein intake does not modulate any of these muscle deconditioning responses.Clinical trial registry number: NCT03797781.
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Diurnal variation in gene expression of human peripheral blood mononuclear cells after eating a standard meal compared with a high protein meal: A cross-over study.
Davis, R, Murgia, C, Dordevic, AL, Bonham, MP, Huggins, CE
Clinical nutrition (Edinburgh, Scotland). 2021;(6):4349-4359
Abstract
BACKGROUND & AIMS Eating at night has been linked to impaired glucose metabolism and dyslipidaemia that is likely a consequence of an underlying disrupted circadian rhythm in metabolic processes. The aim of this study was to explore the gene expression differences after eating a standard test meal or high protein test meal at night compared with the same meal in the morning. METHODS In a cross over design, 10 healthy adults fasted for >10 h and then completed four acute meal challenges at 8am and 8pm on non-consecutive days separated by a wash out, consuming either a high protein low carbohydrate test meal or an isocaloric standard protein and carbohydrate test meal. Fasting and two-hour postprandial blood samples were collected to measure gene expression. For a subset of five participants RNA sequencing was completed on the Illumina NextSeq500. RESULTS The time of day a meal is consumed had an effect on which genes were differentially regulated in the acute postprandial period, with only 6.5% of differentially expressed genes the same both morning and night. More genes were involved in lipid metabolic pathways in the morning and immune pathways at night. RTqPCR analysis of target genes suggested that key regulatory genes responsible for nutrient sensing and lipid and glucose metabolism are differentially expressed at night. These may play a role in improved blood glucose control in peripheral tissues that is observed after eating in the morning but to a lesser extent or not at all at night. Modulation of the macronutrient composition of a meal led to changes in expression of genes involved in the circadian clock and metabolism. CONCLUSIONS Investigating the differences in the transcriptomic response to food at night provides a greater understanding of the mechanisms underlying the changing metabolic phenotypes, characterised by circulating metabolic biomarkers, according to the time of day.
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Urinary Dopamine Excretion Rate Decreases during Acute Dietary Protein Deprivation and Is Associated with Increased Plasma Pancreatic Polypeptide Concentration.
Basolo, A, Hollstein, T, Walter, M, Krakoff, J, Piaggi, P
Nutrients. 2021;(4)
Abstract
Background: Dopamine, a key neurotransmitter in the autonomic nervous system participating in the homeostatic balance between sympathetic and parasympathetic divisions, is involved in food intake regulation. Objective: We investigated whether dopamine is altered by acute fasting or overfeeding diets with varying macronutrient content. Design: Ninety-nine healthy subjects underwent 24-h dietary interventions including eucaloric feeding, fasting, and five different overfeeding diets in a crossover design. Overfeeding diets (200% of eucaloric requirements) included one diet with 3%-protein (low-protein high-fat overfeeding-LPF: 46%-fat), three diets with 20%-protein, and a diet with 30%-protein (44%-fat). Urine was collected for 24 h and urinary dopamine concentration was quantified by high-performance liquid chromatography. Plasma pancreatic polypeptide (PP) concentration, an indirect marker of parasympathetic activity, was measured prior to and after each diet after an overnight fast. Results: During 24-h of fasting, dopamine decreased on average by ~14% compared to eucaloric conditions, whereas PP increased by two-fold (both p < 0.001). Lower dopamine during 24-h fasting correlated with increased PP (r = -0.40, p < 0.001). Similarly, on average urinary dopamine decreased during LPF by 14% (p < 0.001) and lower dopamine correlated with increased PP (r = -0.31, p = 0.01). No changes in dopamine and PP concentrations were observed during other overfeeding diets (all p > 0.05). Conclusions: Dopamine concentrations decrease during short-term fasting and overfeeding with a low-protein diet. As both dietary conditions have in common protein deficit, the correlation between dopamine and PP suggests a compensatory mechanism underlying the shift from sympathetic to parasympathetic drive during dietary protein deprivation.
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GlucoTRIG: a novel tool to determine the nutritional quality of foods and meals in general population.
Thota, RN, Moughan, PJ, Singh, H, Garg, ML
Lipids in health and disease. 2020;(1):83
Abstract
BACKGROUND This study aimed to develop a novel criterion, GlucoTRIG, to rank meals for healthiness, that considers both glycaemic (serum insulin) and lipaemic (serum triglycerides) responses. METHODS Healthy volunteers (n = 10) were recruited with the aim of deriving a standard GlucoTRIG value for a reference meal. Volunteers consumed the reference meal (2 regular slices of wholemeal bread; 250 mL chocolate flavoured milk; 7 g butter and 11 g peanut butter) comprising of carbohydrate, fat and protein (41, 40 and 16% energy respectively) on three different occasions with a minimum washout period of 3 days. The GlucoTRIG value was determined as the difference between the product of insulin and triglyceride obtained from venous blood samples at baseline and the product of insulin and triglyceride at 180 min. RESULTS There were no significant differences in the participants' dietary intakes and their metabolic parameters between three visits (P > 0.005). The GlucoTRIG value obtained from three mean values of the reference meal was found to be 19 ± 3.5. There were no significant (P = 0.2303) differences observed between the GlucoTRIG values for the three visits. CONCLUSION GlucoTRIG, consisting of both glycaemic and lipaemic responses, may be a physiologically relevant tool to rank foods and meals for reducing the risk of metabolic diseases. TRIAL REGISTRATION ACTRN12619000973112.
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Effects of Targeted Versus Adjustable Protein Fortification of Breast Milk on Early Growth in Very Low-Birth-Weight Preterm Infants: A Randomized Clinical Trial.
Bulut, O, Coban, A, Uzunhan, O, Ince, Z
Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition. 2020;(2):335-343
Abstract
BACKGROUND Breast milk is preferred for the feeding of very low-birth-weight (VLBW) infants, but it does not meet nutrition requirements unless it is fortified. Adequate protein intake to maintain the growth of preterm infants cannot be provided by standard fortification methods because of variation in the protein content of human milk. Individualization is necessary to achieve target protein intakes. The goal of this study was to compare the effects of 2 different methods of individualized protein fortification of breast milk on the early growth of VLBW preterm infants. METHODS In a prospective observational study, VLBW preterm infants ≤32 weeks of gestational age were randomized into 2 groups according to the method of breast milk fortification. Anthropometric measurements were performed in both groups weekly for 4 weeks to compare their growth. RESULTS During the trial period, the daily protein intake (targeted vs adjustable fortification groups) was (median [range]) 4.5 (4.4-4.6) vs 4.01 (3.5-4.4) g/kg/d (P = 0.001); the daily weight gains (g/d and g/kg/d; mean ± SD) were 25.7 ± 3.9 vs 22.2 ± 6.4 g/d (P = 0.048) and 23.1 ± 4.3 vs 18.7 ± 4.3 g/kg/d (P = 0.014); and the weekly increase in head circumference was 9.8 ± 1.5 vs 8.4 ± 2.1 mm/wk (P = 0.040). All parameters were significantly higher in the targeted than the adjustable fortification group. CONCLUSIONS Individualized protein fortification using the targeted method for VLBW preterm infants had more positive effects on short-term growth compared with the adjustable fortification method.
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An Application May Help Improve Protein Consumption after Bariatric Surgery.
Estrade, A, Montastier, E, Turnin, MC, Buisson, JC, du Rieu, MC, Tuyeras, G, Hernandez, G, Bérard, E, Ritz, P
Obesity surgery. 2019;(6):1982-1983
Abstract
This brief communication suggests that in patients who had bariatric surgery and in whom protein intake is lower than 60 g/d, the use of an application is likely to improve protein intake.
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Effects of higher habitual protein intake on resistance-training-induced changes in body composition and muscular strength in untrained older women: A clinical trial study.
Nabuco, HC, Tomeleri, CM, Junior, PS, Fernandes, RR, Cavalcante, EF, Nunes, JP, Cunha, PF, Dos Santos, L, Cyrino, ES
Nutrition and health. 2019;(2):103-112
Abstract
BACKGROUND Aging is accompanied by progressive and accentuated decline in muscular strength and skeletal muscle mass, affecting health and functional autonomy. Both resistance training (RT) and diet are strategies that may contribute to improvement in the health of the elderly. AIM: The purpose of this study was to evaluate the effects of higher habitual protein intake on RT-induced changes in body composition and strength in untrained postmenopausal women. METHODS Seventy older women were submitted to an RT program. Body composition, muscular strength, and dietary intake (24 h dietary recall) were performed pre- and post-intervention. To verify different intervention effects according to protein intake of the participants, the sample was separated into tertiles according to protein intake: low, moderate, and high protein intake. RESULTS A time vs. group interaction ( p < 0.05) was observed, with high protein intake presenting greater increases compared with low protein intake, for skeletal muscle mass (5.3% vs. 1.3%), lower limb lean soft tissue (4.9% vs. 1.4%), upper lean soft tissue (4.9% vs. 1.2%), preacher curl (24% vs. 15.2%), and total strength (16.4% vs. 11.7%). A time vs. group interaction ( p < 0.05) was observed, with high protein intake presenting greater increases compared with moderate protein intake, for skeletal muscle mass (5.3% vs. 3.2%). In all groups, a main effect of time ( p < 0.05) was observed for knee extension and chest press. CONCLUSIONS We conclude that intake of >1.0 g/kg/day of protein promotes gains in skeletal muscle mass and muscular strength after RT in untrained older women.
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Optimized calorie and high protein intake versus recommended caloric-protein intake in critically ill patients: a prospective, randomized, controlled phase II clinical trial.
Azevedo, JRA, Lima, HCM, Montenegro, WS, Souza, SCC, Nogueira, IROM, Silva, MM, Muniz, NA
Revista Brasileira de terapia intensiva. 2019;(2):171-179
Abstract
OBJECTIVE To evaluate differences in outcomes for an optimized calorie and high protein nutrition therapy versus standard nutrition care in critically ill adult patients. METHODS We randomized patients expected to stay in the intensive care unit for at least 3 days. In the optimized calorie and high protein nutrition group, caloric intake was determined by indirect calorimetry, and protein intake was established at 2.0 to 2.2g/kg/day. The control group received 25kcal/kg/day of calories and 1.4 to 1.5g/kg/day protein. The primary outcome was the physical component summary score obtained at 3 and 6 months. Secondary outcomes included handgrip strength at intensive care unit discharge, duration of mechanical ventilation and hospital mortality. RESULTS In total, 120 patients were included in the analysis. There was no significant difference between the two groups in calories received. However, the amount of protein received by the optimized calorie and high protein nutrition group was significantly higher compared with the control group. The physical component summary score at 3 and 6 months did not differ between the two groups nor did secondary outcomes. However, after adjusting for covariates, a negative delta protein (protein received minus predetermined protein requirement) was associated with a lower physical component summary score at 3 and 6 months postrandomization. CONCLUSION In this study optimized calorie and high protein strategy did not appear to improve physical quality of life compared with standard nutrition care. However, after adjusting for covariates, a negative delta protein was associated with a lower physical component summary score at 3 and 6 months postrandomization. This association exists independently of the method of calculation of protein target.
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Effect of Macronutrient Composition on Appetite Hormone Responses in Adolescents with Obesity.
Nguo, K, Bonham, MP, Truby, H, Barber, E, Brown, J, Huggins, CE
Nutrients. 2019;(2)
Abstract
Gut appetite hormone responses may be influenced by meal macronutrients and obesity. The primary aim of this study was to examine in adolescents with obesity and of healthy weight the effect of a high-protein and a high-carbohydrate meal on postprandial gut appetite hormones. A postprandial cross-over study with adolescents 11⁻19 years old was undertaken. Participants consumed, in random order, a high 79% carbohydrate (HCHO) and a high 55% protein (HP) meal. Ghrelin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and self-reported appetite were assessed for four hours postprandial. Total energy intake from an ad libitum lunch and remaining 24 h was assessed. Eight adolescents with obesity (OB) and 12 with healthy weight (HW) participated. Compared with HW, OB adolescents displayed a smaller ghrelin iAUC (-25,896.5 ± 7943 pg/mL/4 h vs. -60,863.5 ± 13104 pg/mL/4 h) (p = 0.008) with no effect of meal (p > 0.05). The suppression of ghrelin relative to baseline was similar between OB and HW. Ghrelin suppression was greater following the HP vs. HCHO meal (effect of meal, p = 0.018). Glucose and insulin response were greater following HCHO vs. HP, with responses more marked in OB (time × weight × meal interaction, p = 0.003 and p = 0.018, respectively). There were no effects of weight or macronutrient on GLP-1 or PYY, appetite or subsequent energy intake. The present study demonstrates that dietary protein can modulate postprandial ghrelin responses; however, this did not translate to subsequent changes in subjective appetite or energy intake.
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A High-Fiber Diet Decreases Postabsorptive Protein Turnover but Does Not Alter Insulin Sensitivity in Men with Type 1 Diabetes Mellitus.
Bruttomesso, D, Tessari, P
The Journal of nutrition. 2019;(4):596-604
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Abstract
BACKGROUND High-fiber diets (HFDs) are recommended in the diet of persons with diabetes, yet such diets can impair macronutrient digestion and/or absorption, modify insulin sensitivity, and reset metabolism. OBJECTIVES We studied the effects of a HFD on the kinetics of whole-body protein, a macronutrient that could be affected by dietary fiber, in type 1 diabetes mellitus (T1DM), under both basal-low insulinemic and hyperinsulinemic conditions. METHODS Eight men with T1DM (body mass index range: 21.8-27.8 kg/m2) were studied twice - before and after the addition of guar gum (∼15 g/d) to their usual diet for ∼4 mo. Whole-body protein degradation (i.e., the rate of appearance [Ra] of endogenous leucine), leucine disposal to protein synthesis (PS), deamination, and reamination, were determined before and after the HFD, both in the postabsorptive state and following a euglycemic, hyperinsulinemic, hyperaminoacidemic clamp, using isotope dilution methods. RESULTS After the HFD, mean values (± SEs) for postabsorptive leucine Ra decreased by ∼20%: from 2.52 (0.15) to 2.03 (0.16) μmol x kg-1 x min-1, P < 0.049, after vs. before the HFD respectively. PS also decreased, by ∼25%: from 2.03 (0.15) to 1.57 (0.15), P < 0.045. Leucine concentration (P = 0.1) and reamination (P = 0.095) decreased moderately, whereas deamination was unchanged. Following the clamp, plasma amino acid concentrations (P < 0.001), leucine deamination (+ ∼50%, P < 0.00002), reamination (+ ∼30%, P < 0.0007), and PS (+ ∼35%, P < 0.00001) were all increased compared with postabsorptive state values, whereas endogenous leucine Ra was suppressed (by 15%, P < 0.00001, and by 25%, P < 0.001, with the primary or the reciprocal pool models, respectively). No significant differences in these insulin effects before compared with after the HFD were observed. Metabolic control (glycated hemoglobin), daily insulin requirement, and insulin-mediated glucose disposal were unchanged after the HFD. CONCLUSIONS A HFD downregulates postabsorptive protein turnover in men with T1DM, by decreasing both protein degradation and synthesis, possibly due to a subtle decrease and/or delay in amino acid absorption. It does not significantly affect the insulin (and amino acid sensitivity) to protein turnover, glucose disposal, and metabolic control.